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Magnetic field effects

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https://www.readbyqxmd.com/read/28231298/a-revised-model-for-jeffrey-nanofluid-subject-to-convective-condition-and-heat-generation-absorption
#1
Tasawar Hayat, Arsalan Aziz, Taseer Muhammad, Ahmed Alsaedi
Here magnetohydrodynamic (MHD) boundary layer flow of Jeffrey nanofluid by a nonlinear stretching surface is addressed. Heat generation/absorption and convective surface condition effects are considered. Novel features of Brownian motion and thermophoresis are present. A non-uniform applied magnetic field is employed. Boundary layer and small magnetic Reynolds number assumptions are employed in the formulation. A newly developed condition with zero nanoparticles mass flux is imposed. The resulting nonlinear systems are solved...
2017: PloS One
https://www.readbyqxmd.com/read/28231012/quantum-percolation-and-magnetic-nano-droplet-states-in-electronically-phase-separated-manganite-nanowires
#2
Kaixuan Zhang, Lin Li, Hui Li, Qiyuan Feng, Nan Zhang, Long Cheng, Xiaodong Fan, Yubin Hou, Qingyou Lu, Zhenyu Zhang, Changgan Zeng
One-dimensional (1D) confinement has been revealed to effectively tune the properties of materials in homogeneous states. The 1D physics can be further enriched by electronic inhomogeneity, which unfortunately remains largely unknown. Here we demonstrate the ultra-high sensitivity to magnetic fluctuations and the tunability of phase stability in the electronic transport properties of self-assembled electronically phase-separated manganite nanowires with extreme aspect ratio. The onset of magnetic nano-droplet state, a precursor to the ferromagnetic metallic state, is unambiguously revealed, which is attributed to the small lateral size of the nanowires that is comparable to the droplet size...
February 23, 2017: Nano Letters
https://www.readbyqxmd.com/read/28230974/femtogram-resolution-of-iron-content-on-a-per-cell-basis-ex-vivo-storage-of-human-red-blood-cells-leads-to-loss-of-hemoglobin
#3
Jeffrey J Chalmers, Xiaoxia Jin, Andre Francis Palmer, Peter Amaya, Mark H Yazer, Lee R Moore, Kyoung-Joo Park, X Jeff Pan, Maciej Zborowski
The magnetic characteristics of hemoglobin (Hb) changes with the binding of dioxygen (O2) to the heme prosthetic groups of the globin chains: from paramagnetic ferrous Hb to diamagnetic ferrous oxyhemoglobin (oxyHb) with reversibly bound O2, or paramagnetic ferric methemoglobin (metHb). When multiplied over the number of Hb molecules in a red blood cell (RBC), the effect is detectable through motion analysis of RBCs in a high magnetic field and gradient. This motion is referred to as magnetophoretic mobility which can be conveniently expressed as a fraction of the cell sedimentation coefficient...
February 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28230054/magnetization-switching-in-ferromagnets-by-adsorbed-chiral-molecules-without-current-or-external-magnetic-field
#4
Oren Ben Dor, Shira Yochelis, Anna Radko, Kiran Vankayala, Eyal Capua, Amir Capua, See-Hun Yang, Lech Tomasz Baczewski, Stuart Stephen Papworth Parkin, Ron Naaman, Yossi Paltiel
Ferromagnets are commonly magnetized by either external magnetic fields or spin polarized currents. The manipulation of magnetization by spin-current occurs through the spin-transfer-torque effect, which is applied, for example, in modern magnetoresistive random access memory. However, the current density required for the spin-transfer torque is of the order of 1 × 10(6) A·cm(-2), or about 1 × 10(25) electrons s(-1) cm(-2). This relatively high current density significantly affects the devices' structure and performance...
February 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28230047/electrically-tunable-artificial-gauge-potential-for-polaritons
#5
Hyang-Tag Lim, Emre Togan, Martin Kroner, Javier Miguel-Sanchez, Atac Imamoğlu
Neutral particles subject to artificial gauge potentials can behave as charged particles in magnetic fields. This fascinating premise has led to demonstrations of one-way waveguides, topologically protected edge states and Landau levels for photons. In ultracold neutral atoms, effective gauge fields have allowed the emulation of matter under strong magnetic fields leading to realization of Harper-Hofstadter and Haldane models. Here we show that application of perpendicular electric and magnetic fields effects a tunable artificial gauge potential for two-dimensional microcavity exciton polaritons...
February 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28227937/effects-of-tuning-conditions-on-near-field-of-mri-transmit-birdcage-coil-at-64-mhz
#6
Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov, Elena Lucano, Leonardo M Angelone, Elena Lucano, Leonardo M Angelone, Mikhail Kozlov
This study investigates how the tuning conditions of a 64 MHz / 1.5 T radio frequency (RF) birdcage coil modeled with an RF circuit and 3D electromagnetic co-simulation affect the electric and magnetic near-field distribution. Four models were implemented with different tuning conditions and difference between numerical results and measurements was evaluated. The results show that the simulated near-field depends significantly on coil tuning conditions, especially in volumes close to the ASTM phantom walls...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227862/effects-of-high-frequency-rtms-on-sleep-deprivation-a-pilot-study
#7
D P Martinez-Cancino, J Azpiroz-Leehan, L Jimenez-Angeles, A Garcia-Quintanar, R Santana-Miranda, D P Martinez-Cancino, J Azpiroz-Leehan, L Jimenez-Angeles, A Garcia-Quintanar, R Santana-Miranda, A Garcia-Quintanar, L Jimenez-Angeles, R Santana-Miranda, J Azpiroz-Leehan, D P Martinez-Cancino
Transcranial magnetic stimulation is a neurostimulation technique which has the potential to serve as a unique research tool for investigating a wide variety of fields in cognitive neuroscience. TMS has been approved by the FDA to serve as a treatment to depression and has also been used to evaluate its effects among several conditions such as Alzheimer, Parkinson disease, chronic pain and stroke. High frequency TMS has been previously used with the intention to measure and modulate the negative effects of sleep deprivation in cognitive performance, but there is no consensus about the ideal protocol yet...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227437/effects-of-extremely-low-frequency-electromagnetic-fields-on-in-vitro-cellular-cultures-hela-and-cho
#8
A F Restrepo, V E Tobar, R J Camargo, E Franco, C R Pinedo, O Gutierrez, A F Restrepo, V E Tobar, R J Camargo, E Franco, C R Pinedo, O Gutierrez, C R Pinedo, E Franco, R J Camargo, V E Tobar, O Gutierrez, A F Restrepo
This paper presents the cellular proliferation effects of the exposure to extremely low frequency electromagnetic fields (ELF-EMF) on in-vitro cellular cultures HeLa and CHO. Through the magnetic stimulation system (MSS) the cells were exposed to magnetic fields with sinusoidal waveform at 50 Hz; initially for 40 minutes at intensities of 0.4 mT, 1.4 mT, 2.13 mT, 2.49 mT and 2.53 mT in parallel and perpendicular directions to the culture plates. Subsequently, the repetitive electromagnetic field (rEMF) was applied to 2...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227127/effects-of-the-geometry-and-size-of-the-cerebrospinal-fluid-on-mri-transmit-and-safety-efficiencies-at-300-mhz
#9
Mikhail Kozlov, Pierre-Louis Bazin, Nikolaus Weiskopf, Harald Moller, Mikhail Kozlov, Pierre-Louis Bazin, Nikolaus Weiskopf, Harald Moller, Pierre-Louis Bazin, Nikolaus Weiskopf, Harald Moller, Mikhail Kozlov
We investigated effects of the geometry and size of the cerebrospinal fluid (CSF) on transmit and safety efficiencies in magnetic resonance imaging at 300 MHz. For the human model investigated here and a head position at the top of the RF coil, an increase of CSF space resulted in essential degradation of the safety excitation efficiency without an easily recognizable influence on the magnetic field distribution. For a head location in the coil center, CSF space variation did not significantly change the safety excitation and transmit efficiencies...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226994/high-dielectric-material-in-mri-numerical-assessment-of-the-reduction-of-the-induced-local-power-on-implanted-cardiac-leads
#10
Eugenio Mattei, Elena Lucano, Federica Censi, Leonardo M Angelone, Giovanni Calcagnini, Eugenio Mattei, Elena Lucano, Federica Censi, Leonardo M Angelone, Giovanni Calcagnini, Eugenio Mattei, Giovanni Calcagnini, Elena Lucano, Leonardo M Angelone, Federica Censi
High dielectric materials (HDM) have been proposed in magnetic resonance imaging (MRI) to increase the signal-to-noise ratio (SNR) of the images acquired while reducing the radiofrequency (RF) absorption in tissue. The aim of this study is to assess the potential merit of using HDM to reduce power induced at the tip of an endocardial lead in patients undergoing MRI. Numerical simulations were performed using a commercial finite-differences time-domain (FDTD) software to model the RF field generated by a birdcage body coil at 64 MHz on a human body model...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226463/cardiac-katp-channel-modulation-by-16hz-magnetic-fields-a-theoretical-study
#11
Yuval Aharonovich, Mickey Scheinowitz, Sharon Zlochiver, Yuval Aharonovich, Mickey Scheinowitz, Sharon Zlochiver, Yuval Aharonovich, Sharon Zlochiver, Mickey Scheinowitz
Heart exposure to 16Hz magnetic fields (MFs) was shown to be cardio-protective for diseased hearts; still, the mechanism of this effect is unknown. We hypothesize that a possible one mechanism is an increased trans-membrane KATP channel open probability due to modulation of the degree of dissociation between K(+) ions, having a resonance frequency of 16Hz, and the channel selectivity filter. The Fan-Makielski Markovian KATP channel model was adopted, and the MF bio-effect was manifested by modulating the open probability of the channel using the predictive MF bio-effect parameter based on Binhi's quantum mechanics model...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225813/the-effects-of-cervical-transcutaneous-spinal-direct-current-stimulation-on-motor-pathways-supplying-the-upper-limb-in-humans
#12
Siobhan C Dongés, Jessica M D'Amico, Jane E Butler, Janet L Taylor
Non-invasive, weak direct current stimulation can induce changes in excitability of underlying neural tissue. Many studies have used transcranial direct current stimulation to induce changes in the brain, however more recently a number of studies have used transcutaneous spinal direct current stimulation to induce changes in the spinal cord. This study further characterises the effects following cervical transcutaneous spinal direct current stimulation on motor pathways supplying the upper limb. In Study 1, on two separate days, participants (n = 12, 5 F) received 20 minutes of either real or sham direct current stimulation at 3 mA through electrodes placed in an anterior-posterior configuration over the neck (anode anterior)...
2017: PloS One
https://www.readbyqxmd.com/read/28225578/detection-of-volume-alterations-in-hippocampal-subfields-of-rats-under-chronic-unpredictable-mild-stress-using-7t-mri-a-follow-up-study
#13
Yuefeng Li, Xiaolan Zhu, Shenghong Ju, Jinchuan Yan, Dongqing Wang, Yan Zhu, Fengchao Zang
PURPOSE: To determine hippocampal subfields volume loss in depression, which was simulated by a rat chronic unpredictable mild stress (CUMS) model. As different cellular and molecular characteristics in hippocampal subfields, these subfields are regarded as differentially vulnerable to processes associated with stress. MATERIALS AND METHODS: Twenty male Wistar rats were exposed to various stressors until the model was successfully established. The effects of physical exercise on recovery of hippocampal volume in depressed rats were simulated using the wheel running test (WRT)...
February 22, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28223488/large-nonsaturating-magnetoresistance-and-signature-of-nondegenerate-dirac-nodes-in-zrsis
#14
Ratnadwip Singha, Arnab Kumar Pariari, Biswarup Satpati, Prabhat Mandal
Whereas the discovery of Dirac- and Weyl-type excitations in electronic systems is a major breakthrough in recent condensed matter physics, finding appropriate materials for fundamental physics and technological applications is an experimental challenge. In all of the reported materials, linear dispersion survives only up to a few hundred millielectronvolts from the Dirac or Weyl nodes. On the other hand, real materials are subject to uncontrolled doping during preparation and thermal effect near room temperature can hinder the rich physics...
February 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28222160/soret-and-dufour-effects-on-mhd-peristaltic-transport-of-jeffrey-fluid-in-a-curved-channel-with-convective-boundary-conditions
#15
Tasawar Hayat, Hina Zahir, Anum Tanveer, Ahmad Alsaedi
The purpose of present article is to examine the peristaltic flow of Jeffrey fluid in a curved channel. An electrically conducting fluid in the presence of radial applied magnetic field is considered. Analysis of heat and mass transfer is carried out. More generalized realistic constraints namely the convective conditions are utilized. Soret and Dufour effects are retained. Problems formulation is given for long wavelength and low Reynolds number assumptions. The expressions of velocity, temperature, heat transfer coefficient, concentration and stream function are computed...
2017: PloS One
https://www.readbyqxmd.com/read/28221040/magnetic-fullerene-dna-hyaluronic-acid-nanovehicles-with-magnetism-reduction-dual-responsive-triggered-release
#16
Ling Wang, Yitong Wang, Jingcheng Hao, Shuli Dong
We create the dual-responsive nanovehicle that can effectively combine and abundantly utilize magnetic and glutathione (GSH)-reductive triggers to control the drug delivery and achieve more intelligent and powerful targeting. In the nanovehicles, paramagnetic fullerene (C60@CTAF) was prepared via one-step modification of fullerene with magnetic surfactant CTAF by hydrophobic interaction for the first time. The perfect conjugation of C60 and CTAF increased the solubility or dispersity of fullerenes and qualify CTAF with more powerful assembly capability with DNA...
February 21, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28220875/theory-of-topological-insulator-waveguides-polarization-control-and-the-enhancement-of-the-magneto-electric-effect
#17
J A Crosse
Topological insulators subject to a time-reversal-symmetry-breaking perturbation are predicted to display a magneto-electric effect that causes the electric and magnetic induction fields to mix at the material's surface. This effect induces polarization rotations of between ≈1-10 mrad per interface in an incident plane-polarized electromagnetic wave normal to a multilayered structure. Here we show, theoretically and numerically, that by using a waveguide geometry with a topological insulator guide layer and magneto-dielectric cladding it is possible to achieve rotations of ≈100 mrad and generate an elliptical polarization with only a three-layered structure...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220858/time-reversal-breaking-induced-quantum-spin-hall-effect
#18
Wei Luo, D X Shao, Ming-Xun Deng, W Y Deng, L Sheng
We show that quantum spin Hall (QSH) effect does not occur in a square lattice model due to cancellation of the intrinsic spin-orbit coupling coming from different hopping paths. However, we show that QSH effect can be induced by the presence of staggered magnetic fluxes alternating directions square by square. When the resulting Peierls phase takes a special value , the system has a composite symmetry ΘΡ- with Θ the time-reversal operator and Ρ- transforming the Peierls phase from γ to γ - , which protects the gapless edge states...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220173/spin-polarized-transport-in-graphene-nanoribbons-with-rashba-spin-orbit-interaction-the-effects-of-spatial-symmetry
#19
Qingtian Zhang, K S Chan, Jingbo Li
We study the spin-dependent transport properties of graphene nanoribbons with Rashba spin-orbit interaction (SOI). It is found that highly spin polarized electrical currents can be produced in asymmetrically-notched graphene nanoribbons, and the polarization components are found to be along the x, y and z directions. The spin polarization is largely enhanced by breaking the spatial symmetries of ideal graphene nanoribbons with Rashba SOI, and the spin polarized electrical currents with higher flexibility in the orientation of the polarization can be generated...
February 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28220066/modulation-of-auditory-evoked-magnetic-fields-elicited-by-successive-frequency-modulated-fm-sweeps
#20
Hidehiko Okamoto, Ryusuke Kakigi
In our daily life, we are successively exposed to frequency-modulated (FM) sounds that play an important role in speech and species-specific communication. Previous studies demonstrated that repetitive exposure to identical pure tones resulted in decreased neural activity. However, the effects of repetitively presented FM sounds on neural activity in the human auditory cortex remain unclear. In the present study, we used magnetoencephalography to investigate auditory evoked N1m responses elicited by four successive temporally repeated and superimposed FM sweeps in three sequences: (1) four FM sweeps were identical, (2) four FM sweeps had the same FM direction and rate, but different carrier frequencies, (3) four FM sweeps differed with respect to the FM rate and/or direction and their carrier frequencies...
2017: Frontiers in Human Neuroscience
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